A Steric-Hindrance-Induced Weakly Solvating Electrolyte Boosting the Cycling Performance of a Micrometer-Sized Silicon Anode

The application of micrometer-sized silicon (mSi) is challenging due to the severe volume change during cycling, resulting in serious pulverization of the mSi and detachment of active materials from the current collector and consequently causing a capacity loss. Here, a new LiPF6-compatible ether electrolyte is developed to enhance the cycling performance of the mSi anode. Ethylene glycol dibutyl ether (EGDE) with large steric hindrance renders PF6–-rich solvation complexes in the electrolyte, which are favorable for rapidly passivating the mSi anode surface and forming a LiF-rich, thin, and stratified solid electrolyte interphase (SEI). As a result, the mSi anode displays a high capacity retention of 1901 mAh g–1 after 500 cycles and a high CE of 99.92% in a medium-concentration EGDE-LiPF6-based electrolyte. This work provides an effective strategy for extending the cycling life of the mSi anode by designing a new LiPF6-ether electrolyte system.